EAGER: Testing the Roles of Zygotic Selection and Sperm Competition in Transmission Bias in Astyanax

EAGER：测试 Astyanax 中合子选择和精子竞争在传播偏差中的作用

• 批准号: 1525047
• 负责人: Richard Borowsky
• 金额: $ 20万
• 依托单位: New York University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1525047&HistoricalAwards=false
• 关键词: EAGER; Testing; Roles; Zygotic; Selection

It has been accepted that the characteristics of sperm are determined by the diploid genotype of the male producing them. However, recent and unexpected findings indicate that the phenotype of a sperm cell may also be influenced by its own genotype. This innovative project examines the degree to which the haploid genotypes of sperm cells affect their individual characteristics and the relative importance of sperm competition versus selection post-fertilization in causing biases in transmission of alleles from one generation to the next. It will provide basic information to illuminate a previously unsuspected but potentially important avenue for natural selection in evolution. The expected results have the potential to open up an important new line of research in sperm biology. They are expected to have broad implications in developmental biology, evolutionary biology, and for improvements in reporductive technologies in humans and domestic animals.This research investigates the epistatic interactions among genes observable in hybrids between two incipient species of freshwater fish (Astyanax spp.). Previous work has shown that sperm from hybrid males pass along biased subsets of alleles and allelic combinations derived from unlinked genes. This observation suggested the hypothesis that the phenotypes of individual sperm (in this case fertilization efficiency) are determined by their individual genotypes, i.e., the probability that a package gets delivered depends upon what it contains. Consistent with this hypothesis are preliminary studies that show that sperm subpopulations - defined by differences in swimming ability or by their response to a chemical challenge - differ significantly in allelic content. This research tests whether the observed transmission biases are indeed caused by sperm competition or whether there is a contribution from zygotic selection, post fertilization. Single sperm will be genotyped from embryos formed using intracytoplasmic sperm injection. This will allow different sub-populations of sperm (e.g. slow versus fast swimmers) to be compared for allelic content. Additionally, the offspring of hybrid X non-hybrid individuals will be genotyped, allowing for the detection of transmission biases. The hypothesis predicts that biases will be restricted to families derived from hybrid males but not from hybrid females.

人们普遍认为，精子的特征是由产生精子的雄性的二倍体基因型决定的。 然而，最近的意外发现表明，精子细胞的表型也可能受到其自身基因型的影响。这一创新项目研究了精子细胞的单倍体基因型对其个体特征的影响程度，以及精子竞争与受精后选择在导致等位基因从一代传递到下一代的偏差方面的相对重要性。它将提供基本信息来阐明进化中自然选择的一条先前未被怀疑但可能重要的途径。预期结果有可能开辟精子生物学重要的新研究领域。它们预计将对发育生物学、进化生物学以及人类和家畜生殖技术的改进产生广泛的影响。这项研究调查了两种早期淡水鱼（Astyanax spp.）物种之间的杂交中可观察到的基因之间的上位相互作用。先前的研究表明，来自杂交雄性的精子会传递来自不连锁基因的等位基因和等位基因组合的有偏差的子集。这一观察结果提出了这样一个假设：单个精子的表型（在这种情况下是受精效率）是由其各自的基因型决定的，即包裹被递送的概率取决于它所包含的内容。与这一假设一致的是，初步研究表明，精子亚群（由游泳能力差异或对化学挑战的反应定义）的等位基因含量存在显着差异。这项研究测试了观察到的传播偏差是否确实是由精子竞争引起的，或者是否有受精后合子选择的影响。将从使用胞浆内精子注射形成的胚胎中对单个精子进行基因分型。这将允许比较不同精子亚群（例如游得慢与游得快）的等位基因含量。此外，还将对杂交 X 非杂交个体的后代进行基因分型，以便检测传播偏差。该假说预测，偏见将仅限于混血男性的家庭，而不是混血女性的家庭。